Input devices, including proximity sensor devices (e.g., touchpads or touch sensor devices), are widely used in a variety of electronic systems. A proximity sensor device typically includes a sensing region, often demarked by a surface, in which the proximity sensor device determines the presence, location and/or motion of one or more input objects. Proximity sensor devices may be used to provide interfaces for the electronic system. For example, proximity sensor devices are often used as input devices for larger computing systems (such as opaque touchpads integrated in, or peripheral to, notebook or desktop computers). Proximity sensor devices are also often used in smaller computing systems (such as touch screens integrated in cellular phones).
Moreover, input devices may be integrated into display devices. However, various problems exist in such an integration. For example, to produce a force-sensitive display device, force sensors within the display device may need to detect an input force through several layers of a display device, e.g., through several layers devoted to proximity sensing or performing various display functions.